builder/digitalocean: give up on graceful shutdown more quickly

builder/digitalocean/step_power_off.go

@@ -38,6 +38,7 @@ func (s *stepPowerOff) Run(state multistep.StateBag) multistep.StepAction {
 		return multistep.ActionHalt
 	}
 
+	log.Println("Waiting for poweroff event to complete...")
 	err = waitForDropletState("off", dropletId, client, c.stateTimeout)
 	if err != nil {
 		state.Put("error", err)
@@ -45,7 +46,6 @@ func (s *stepPowerOff) Run(state multistep.StateBag) multistep.StepAction {
 		return multistep.ActionHalt
 	}
 
-	log.Println("Waiting for poweroff event to complete...")
 	return multistep.ActionContinue
 }
 

builder/digitalocean/step_shutdown.go

@@ -12,6 +12,7 @@ type stepShutdown struct{}
 
 func (s *stepShutdown) Run(state multistep.StateBag) multistep.StepAction {
 	client := state.Get("client").(*DigitalOceanClient)
+	c := state.Get("config").(config)
 	ui := state.Get("ui").(packer.Ui)
 	dropletId := state.Get("droplet_id").(uint)
 
@@ -19,28 +20,51 @@ func (s *stepShutdown) Run(state multistep.StateBag) multistep.StepAction {
 	// of times because sometimes it says it completed when it actually
 	// did absolutely nothing (*ALAKAZAM!* magic!). We give up after
 	// a pretty arbitrary amount of time.
-	var err error
 	ui.Say("Gracefully shutting down droplet...")
-	for attempts := 1; attempts <= 10; attempts++ {
-		log.Printf("ShutdownDroplet attempt #%d...", attempts)
 	err := client.ShutdownDroplet(dropletId)
 	if err != nil {
+		// If we get an error the first time, actually report it
 		err := fmt.Errorf("Error shutting down droplet: %s", err)
 		state.Put("error", err)
 		ui.Error(err.Error())
 		return multistep.ActionHalt
 	}
 
-		err = waitForDropletState("off", dropletId, client, 20*time.Second)
-		if err == nil {
-			break
-		}
+	// A channel we use as a flag to end our goroutines
+	done := make(chan struct{})
+	shutdownRetryDone := make(chan struct{})
+
+	// Make sure we wait for the shutdown retry goroutine to end
+	// before moving on.
+	defer func() {
+		close(done)
+		<-shutdownRetryDone
+	}()
+
+	// Start a goroutine that just keeps trying to shut down the
+	// droplet.
+	go func() {
+		defer close(shutdownRetryDone)
+
+		for attempts := 2; attempts > 0; attempts++ {
+			log.Printf("ShutdownDroplet attempt #%d...", attempts)
+			err := client.ShutdownDroplet(dropletId)
+			if err != nil {
+				log.Printf("Shutdown retry error: %s", err)
 			}
 
+			select {
+			case <-done:
+				return
+			case <-time.After(20 * time.Second):
+				// Retry!
+			}
+		}
+	}()
+
+	err = waitForDropletState("off", dropletId, client, 2 * time.Minute)
 	if err != nil {
-		state.Put("error", err)
-		ui.Error(err.Error())
-		return multistep.ActionHalt
+		log.Printf("Error waiting for graceful off: %s", err)
 	}
 
 	return multistep.ActionContinue